PSYCH 303 Chapter Notes - Chapter 11: Blind Experiment, Construct Validity, Observational Error

• School: U of M
• Department: Psychology
• Course: PSYCH 303
• Professor: Colleen Seifert

Document Summary

Psychology 303 chapter 11: more on experiments: confounding and obscuring variables. Threats to internal validity: did the independent variable really cause the difference: three most common threats to internal validity are design confounds, selection effects, and. If they do use a pretest, they might opt to use alternative forms of the test for the two measurements: might both measure the same thing, a comparison group can help. Instrumentation threats to internal validity: an instrumentation threat or decay, occurs when a measuring instrument changes over time. In observational research, the people who are coding behaviors are the measurement instruments, and they might change their standards for judging behavior over time. If different forms are used for the pretest and posttest, but the two forms are not sufficiently equivalent, this can also lead to instrumentation threats: preventing instrumentation threats, use a posttest only design, behavior is only measured once.